Summary On 29 October 2006, at approximately 0045 eastern standard time, the barge OTM3072, carrying a cargo of bulk wood chips, capsized while under tow by the tug OceanFoxtrot in a strong gale about six nautical miles north of Bas-Caraquet, New Brunswick. There was no injury, but the barge was declared a constructive total loss. Ce rapport est galement disponible en franais. Other Factual Information Particulars of the Vessels Description of the Vessel The barge OTM3072 was made of steel. The hull was subdivided by three longitudinal bulkheads and six transverse bulkheads into 26watertight compartments3 (see AppendixA). Uprights and wire mesh form a 12.19m-high enclosure around the outside of the deck to contain dry bulk cargo. History of the Voyage On 19 October 2006, the tug OceanFoxtrot sailed from Cacouna, Quebec, for Sheet Harbour, Nova Scotia, with eight crew members on board and the empty barge OTM3072 in tow. On October 25, when the two vessels arrived in Sheet Harbour, a private marine surveyor conducted a draught survey of the barge for chartering purposes. The master of the OceanFoxtrot left the first mate and a supernumerary mate in training to supervise the loading. No stability calculations for the barge load were carried out before or after loading. The draughts were measured a second time once loading was completed, and it was determined that 5563tonnes of bulk wood chips had been loaded on deck (see Figure2). On October 26 at 0240,4 the tug and barge sailed from Sheet Harbour, bound for Cap-de-la-Madeleine, Quebec. Because of the time of year and to avoid forecast high waves and strong winds in Cabot Strait and Northumberland Strait, the master chose a route across the Strait of Canso (see AppendixB). The tug and barge arrived safely at Mulgrave, Nova Scotia, and were secured overnight. On October 27 at approximately 1030, the tug and barge sailed from Mulgrave into northwesterly headwinds of 20to 25knots and waves of approximately 2m. Because the barge was towing well and the weather was forecast to improve, the master decided to continue on a course to the north of Prince Edward Island. The next day, October28, the tug and barge received a new weather forecast predicting southeasterly winds varying from moderate to storm force. The tug and tow then altered course to seek shelter behind Miscou Island, New Brunswick. At approximately 1850, the vessels were about seven miles north of Bas-Caraquet, New Brunswick (see Figure1, positionA). In order to manuvre within an area off Bas-Caraquet (see the circle in Figure1), the crew found it helpful to alternate between heading into the wind and then running with it. At the start of the manuvre, the winds were southeasterly with gusts up to 28knots. During the evening, the weather conditions worsened; the steady winds increased to 24knots with gusts up to 50knots. At reduced speed, the tug was rolling and pitching in 1to 2m seas. Heavy rain was scrambling the barge's echo on the radar to the point where the crew had difficulty monitoring the barge.5 At midnight on October28, the master handed the watch over to the first mate. The navigation lights on the barge were visible, and the tow was under control. At 0040 on October29, at 4753.99'N, 06449.43'W (see Figure1, positionB), the tug swung to port to head northeast. At 0045, the first mate noted that the tug and barge were becoming increasingly difficult to handle and the barge's navigation lights were no longer visible. At about 0100, the first mate informed the master of this situation, adding that both vessels were drifting. At daybreak (approximately 0400), when the tug was at position 4758.5'N, 06457.4'W (see Figure1, positionC), the crew discovered that the barge had capsized and the towline was still attached to it. At 1015, after consulting with the managing owner on shore, the tug towed the capsized barge to Gasp, Quebec, where both vessels arrived at about 2000on 30October2006. The barge remained anchored and capsized at that location until being righted in May2007. Load Details The OTM3072 was loaded on 26October2006 at Sheet Harbour as follows (see Figure2): wood chips were loaded to a maximum height of 13.72m, for a total of 5563tonnes; the port and starboard No.5 outer compartments were partially filled and the port and starboard after peaks were completely filled, giving a total of 458tonnes of ballast water; two power shovels used for unloading, weighing 47and 49tonnes respectively, were stowed on the cargo in the after part of the barge, more than 7m above the deck; the mean draughts at the forward and aft marks were 4.53m and 5.11m, respectively. Damage to the Barge and the Environment The two power shovels and cargo were lost when the barge capsized. A post-occurrence underwater inspection found significant damage to the base of the reinforcing and support structure of the uprights around the deck. Afterward, the barge was declared a constructive total loss. In May 2007, during operations to right the barge, cracks were observed on several welds on the bottom plates. Manhole covers on deck were found not fully tightened. Certification and Crew Experience Tug and Barge Certification At the time of the occurrence, the OceanFoxtrot had a valid inspection certificate, as a non-passenger ship, issued by Transport Canada (TC). The OTM3072 was not subject to any TC inspection. Crew Certification and Experience The master held a master mariner certificate of competency and had 29years of experience in towing activities, but only a few voyages with a load of wood chips. The first mate held a watchkeeping mate certificate of competency. He had 8years' experience in towing activities and had been sailing on the OceanFoxtrot since2004. The supernumerary mate in training held a command endorsement for the watchkeeping mate certificate of competency. This was his first voyage on the OceanFoxtrot. Before this, he served as captain on the OceanEchoII with the barge Betsiamites. Company Structure The managing owner of the OceanFoxtrot and OTM3072 is part of a holding company grouping together companies that offer the following complementary services on Canada's East Coast: towing, naval and industrial construction and repair, marine salvage, wreck salvage, underwater intervention, and dredging. The parent company owns, maintains, and operates a fleet of 26tugs and about 150barges. Each subsidiary is responsible for hiring and training its crew and developing its own operating procedures. At the time of the occurrence, the managing owner operated two tug/barge configurations to carry wood chips: the OceanFoxtrot with the barge OTM3072, and the OceanEchoII with the barge Betsiamites. Barge Modifications and Stability After its construction in 1972, load lines were assigned to the barge by the classification society American Bureau of Shipping. In order to comply with United States stability standards,6 a letter from the classification society, appended to the load line certificate, limited the height of the cargo's centre of gravity, depending on the draught,7 as set out in the following table: In 1998, the managing owner acquired the OTM3072 in the UnitedStates and registered it in Canada on 18October 1999. Over the next few years, the barge was contracted to carry logs. In 2003, 7.62m uprights were added around the outside of the deck to retain cargo. The amount of cargo carried was then gradually increased over a period of several years without the assistance of a loading manual or stability booklet. Following the addition of the uprights, ballast water was added to lower the centre of gravity and improve the barge's trim and stability. The barge, however, was not equipped with a ballast system. Ballasting of the compartments was done using a portable pump that was moved from compartment to compartment around the edge of the barge, outside the uprights. The Nos.4 and 5 outer watertight compartments and the aft port and starboard peaks thus became ballast tanks.8 In the summer of 2005, a new contract to transport 17500m3 of wood chips was obtained and the OTM3072 was further modified. Plans and summary stability calculations to increase the height of the uprights- to 12.19m- were first done by the managing owner's technical department. These calculations made it possible to establish the approximate value of the initial metacentric height above the keel (KM), the height of the barge's centre of gravity above the keel (KG), and the metacentric height (GM), which gave an indication of the stability in the upright condition only, but no indication of the stability at large angles of heel. The managing owner then gave a consulting naval architect the data on the barge's characteristics and the planned structural modifications so that the naval architect could do more detailed stability calculations for fully loaded conditions - estimated at 5950tonnes of cargo. Without waiting for a response, however, the company modified the barge according to the summary plans and calculations. The naval architect's calculations were based on an estimate of the weight of the structural modifications. Moreover, because no internal inspection of the compartments had been done, the calculations were also based on a summary verification of the lightship displacement. The results of these calculations showed that the barge's stability was below the criteria specified in STAB8.9 This standard, however, did not apply to the OTM3072;10 the naval architect therefore sent a letter to the managing owner to inform that the standard could only serve as a guide for assessing vessel stability. Similarly, the naval architect issued an opinion that the barge's stability was sufficient for "average" weather,11 with the final decision to sail up to the master, who was urged to consider the following points: weather conditions, particularly wind, waves and spray (which can wet cargo and reduce stability), and the effect of specific wind strengths on list; the need to keep watertight compartments dry; the loaded vessel will need to be even keel and without list; a minimum freeboard of 1.3m will need to be maintained; and the vessel should never heel more than 5 - the point at which water would flow onto the deck and rapidly decrease stability. (In such a case, the master would have to find a "point of sailing" that minimizes heel, and seek out a port of refuge.) The naval architect's calculations- which were based on preliminary data- showed that the area under the GZcurve was 0.05metre-radians, which is about 62percent of the area required by STAB8. However, a post-occurrence examination by the TSB revealed that the area under the GZcurve was 0.02metre-radians, which is about 25percent of the area required by the standard. The fall of 2005 was a test period for the barge's new operations. During this period, the managing owner realized that the barge had a smaller cargo capacity than planned. A copy of the naval architect's letter was given to the master of the OceanFoxtrot only after the first voyage under the new contract, which was made from 20to 22October2005. On 27October2005, in a memorandum addressed to the managing owner's operations supervisor, the master expressed doubts as to the accuracy of the data given to the naval architect. The master suggested providing the naval architect with more precise data because, in his experience, stability was likely being affected by this inaccuracy and the barge was already operating at the limits of its capacity. The managing owner did not act on the master's memorandum, the naval architect was not informed that calculations might have to be revised, and no stability booklet or loading instructions were given to the master. In addition, the naval architect's recommendations regarding the operational limitations were not followed, particularly those concerning the ballast, list, trim, and freeboard. Following this occurrence, the TSB assessed the barge's stability from its arrival at Sheet Harbour on 25October2006 until capsizing on 29October2006.12 The loading condition upon departing Sheet Harbour was found to be as follows: the wood chips weighed 5902tonnes (not 5563tonnes); the No. 5 compartments and the after peaks contained 513tonnes of ballast water (not 458tonnes); a "constant" of 356tonnes, representing all unidentifiable weights, had to be considered in order to comply with the most recent lightship displacement, established in October2005; and the load distribution was such that the barge had a trim by the stern of 0.57m and a list to port of more than 2; the effect of the trim and list reduced the freeboard, in particular on the port quarter, to 0.28m. Barge Stability Calculations Each master was free to load the barge as he felt was best, though the managing owner sought to maximize loading per voyage and closely monitored the amount of cargo carried. In 2003, the master in charge of the OTM3072 undertook to increase the amount of cargo carried. With no stability data other than a deadweight scale, he prepared a calculation sheet to help determine the approximateGM. The result, approximately 2m, reassured him of the barge's stability. The GM value was the only stability assessment that this master made until he left the company in2006. In June 2006, his replacement, who was uncomfortable with stability calculations, asked for assistance with this task. Using the basic information available for the barge- which was the deadweight scale, volume and centre of gravity of each of the compartments, and an estimated block coefficient- a customized electronic spreadsheet was created by the managing owner for this second master.13 The electronic spreadsheet's accuracy was not verified by a naval architect, classification society, or byTC. For the voyage departing 26October2006, a third master- who was aware of the electronic spreadsheet's limitations- chose not to use it to determine the barge's stability. Safety Management System It is generally recognized that the functional requirements of a good safety management system include: a safety and environmental- protection policy; instructions and procedures to ensure safe operation of ships and protection of the environment in compliance with relevant legislation; defined levels of authority and lines of communication between and among shore and shipboard personnel; procedures for reporting accidents and non-conformities; designation of a person or persons ashore to monitor the safety- and pollution-prevention aspects of the operation of each ship. Such a person would require direct access to the highest level of management; procedures to prepare for and respond to emergency situations; and procedures for internal audits and management reviews. At the time of the occurrence, the parent company had obtained ISO9001-2000 accreditation and had voluntarily begun complying with the ISMCode. However, that approach had not yet been adopted group-wide by subsidiary companies such as the managing owner of the tug and barge. As a result, the master was responsible for safety management on board the OceanFoxtrot. There were no directives or procedures to guide shore-based and shipboard personnel. Prior Occurrences Before this occurrence, the OTM3072 was involved in three occurrences of note. In July 2005, the barge OTM3072 struck the wharf in a mooring manuvre, damaging its starboard skeg. The barge continued operations, but the master noticed that it had a tendency to drift strongly to port. Although the master reported this to the managing owner, no repairs were made. On 31 October 2005, the tug OceanFoxtrot, towing the OTM3072, caused two close-quarters situations in the same day. The TSB and TC attended. While on board, TSB investigators were able to observe the condition of the load and questioned the barge's stability. In January2006, in a Marine Safety Information (MSI) letter, the TSB suggested that the managing owner undertake appropriate measures to ensure the barge's safety in terms of stability.14 The master of the OceanFoxtrot was not immediately informed of TSB's MSI letter. It was not until 29May2006 that he became aware of it via TSB representatives. On 14June2006, in response to TSB's MSI letter, the master stated in a letter addressed to the managing owner that he would limit the height of the cargo to 12.19m (the height of the wire mesh/uprights) and keep the barge's trim at the UnitedStates-assigned load lines. Tug and Barge Working Group In 2005, TC informed the TSB that a working group had been formed to examine tug/barge issues. This group presented its findings to the TC Marine Safety Executive Committee (MSE)15 in 2005and to the Canadian Marine Advisory Council (CMAC) in May2006, noting in particular the following issues: certification of winches and towing equipment, and standardization of bollard pull ratings; construction standards for barges not covered by the Oil Barge Standards (TP11960); operational practices for tug/barge combinations, including occupational health and safety standards; operational practices for tug/barge combinations in ice; safe crewing of tug/barge combinations; and lighting of push-mode tug/barge combinations under the Collision Regulations. Statistics According to the information gathered from TCand Statistics Canada, more than 1450barges with a tonnage exceeding 100are currently registered in Canada. These carry 30to 40million tonnes of cargo peryear in Canada and the UnitedStates. According to the TSB database, 21capsizings involving barges have been reported since1998.16 The majority of these were due to: limited transverse stability, resulting in improper loading; or a loss of transverse stability in rough weather, downflooding of one or more of the watertight compartments, or improper cargo stowage.